DETERMINANTS OF SUCCESSFUL NONTHORACOTOMY CARDIOVERTER-DEFIBRILLATOR IMPLANTATION - EXPERIENCE IN 101 PATIENTS USING 2 DIFFERENT LEAD SYSTEMS

Objectives. This study was conducted to identify the determinants of s uccessful nonthoracotomy cardioverter-defibrillator implantation. Back ground. Until recently, either median sternotomy or thoracotomy was ne cessary to implant the electrodes used for internal cardioverter-defib rillator systems. A number of manufacturers have developed nonthoracot omy lead systems comprising two transvenous coil electrodes and a subc utaneous patch electrode. At present, the factors associated with the success or failure of a nonthoracotomy approach are unknown. Methods. A total of 101 consecutive patients requiring a cardioverter-defibrill ator underwent an initial nonthoracotomy approach. Factors associated with successful nonthoracotomy implantation were prospectively determi ned. Results. A nonthoracotomy system was implanted in 72 (71%) of 101 patients. Twenty-nine patients (29%) required thoracotomy. Univariate predictors of successful nonthoracotomy implantation included smaller cardiac size (p < 0.0001), smaller cardiothoracic ratio (p < 0.0002), QRS duration < 120 ms (p = 0.003), female gender (p = 0.006), ventric ular fibrillation as the presenting arrhythmia (p = 0.03) and smaller echocardiographic left ventricular size (p = 0.04). Multivariate predi ctors included smaller cardiac size (p < 0.002) and female gender (p < 0.007). Total actuarial survival over a mean (+/- SD) follow-up inter val of 12 +/- 7 months was 91 +/- 0.03% and was not different in the t horacotomy and nonthoracotomy groups. Conclusions. A nonthoracotomy ca rdioverter-defibrillator system can be implanted in a majority of pati ents. Smaller cardiac size and female gender are associated with a hig h probability of successful implantation.